【作者】 李宁；

【导师】 史家顺；

【作者基本信息】 东北大学 ， 机械工程（专业学位）， 2017， 硕士

【摘要】 搅拌摩擦焊(Friction Stir Welding,FSW)是一种新型固相连接技术,由英国焊接所(TWI)于1991年发明并申请专利,目前正在世界范围内受到越来越多的关注,是自激光焊接技术发明以来最具革命性的一项焊接技术。该技术的发展对于提高现代制造技术,尤其是航空制造技术具有十分重要的意义。搅拌摩擦焊接技术的一系列优点,已经完全成为传统熔焊技术无法相比的焊接技术,在一定层面上,搅拌摩擦焊已经迅速取代了传统熔焊,在各大应用领域发挥着其不可代替的作用。搅拌摩擦焊接过程是一个十分复杂的过程,其中搅拌头轴肩的下压力(焊接压力)和下压量是十分重要而又关系密切的两个工艺参数。经过研究发现,在搅拌头旋转速度和焊接速度等条件不变的情况下,搅拌头轴肩的下压力和下压量呈一定的正相关关系,而且在稳定焊接状态下,两者之间甚至存在某种固定的函数关系。本文以东北大学材料科学与工程学院自主研发设计的龙门式搅拌摩擦焊试验机为载体,提出了搅拌摩擦焊接过程当中搅拌头轴肩下压力和下压量的测量方法,并进行了一些机床相关的研究工作。本文的主要研究内容包括:(1)试验机的三维建模与仿真分析。对试验机整体进行三维建模,并结合搅拌摩擦焊接过程的力学特点,对试验机中几个承载较大的零部件进行力学分析,校核其是否满足焊接过程中的强度和刚度要求,并对主轴和试验机整体进行模态分析。(2)无线测力刀柄的设计。针对焊接过程下压力的测量需求,对焊接过程中搅拌头的受力情况进行了分析,结合搅拌摩擦焊的工艺特点,提出了无线测力刀柄的设计思路,对刀柄内部传感器进行理论分析,制作出测力刀柄实物。(3)刀柄传感器的静态加载实验研究。针对焊接过程中搅拌头的复杂受力情况,通过设计实验夹具对所选用的称重传感器进行不同受力条件下的静态加载实验,探究称重传感器在各个受力状态下的实际信号输出变化规律,并分析其对最终测量结果的影响。(4)无线测力刀柄的实验。通过无线测力刀柄的静态加载试验和焊接实验,探究测力刀柄的实际测量精度,并进行误差分析。(5)搅拌头轴肩下压量测量控制系统的设计。针对焊接过程下压力的测量需求,对焊接过程中搅拌头的运动过程进行了分析,提出基于光栅尺和PLC的搅拌头位置闭环控制系统的设计思路。更多还原

【Abstract】 Friction Stir Welding(FSW)is a new type of solid phase connection technology that invented and patented by The Welding Institute(TWI)in 1991.FSW is the most revolutionary welding technology since the invention of laser welding technology and is now by more and more attention all over the world.The development of this technology is of great significance for the improvement of modern manufacturing especially the aviation manufacturing technology.FSW has become a welding technology that traditional fusion welding technology cannot compared with completely by reason of its series of advantages.It has rapidly replaced the traditional fusion welding in some ways and is playing the effect that cannot be replaced in each of its application field.FSW is a very complicated process and vertical force and plunge depth of the tool shoulder are two of the very important process parameters.Some researches show us that the two parameters present a certain positive correlation relationship when other process parameters unaltered and even a kind of constant function relationship during stable welding conditions.This subject undertakes some necessary researches about the measurements of vertical force and plunge depth of the tool shoulder during the process of welding based on a gantry type FSW experiment machine that designed and manufactured by the School of Materials Science and Engineer of Northeastern University.It comes up with the measuring methods of the two process parameters during welding and conducts some relevant researches about the structure of the machine.Research contents of this subject mainly include:(1)Builds the 3D model of the whole FSW experiment machine,and makes mechanical analysis about some large forced parts in it to check the strength during welding.(2)Comes up with the design idea of wireless force measuring shank combining with the technology characteristics of FSW after making a analysis for the force condition of the FSW tool according to the welding process,and finishes the dynamic calibration experiment of the wireless force measuring shank.(3)Finishes the static loading experiment of the weighing sensor inside of the shank and gets the output signal changing characteristics of the sensor in the situations of different loaded.(4)Comes up with the design idea of the plunge depth measuring device after analyzing the motion course of the FSW tool.Makes use of a linear scale to translate the displacement signal of the tool into the digital impulse signal and passes it to the PLC by the serial port.更多还原